1. Field of the Invention
The present invention relates to a plasma display module, and more particularly, to a plasma display module having an improved circuit substrate grounding structure suitable to be used to manufacture a slim and light weighted display module.
2. Description of the Related Art
Plasma display modules are flat panel display modules that display images by using a discharge effect. Due to their very good characteristics, such as high display capacity, high brightness, high contrast, high performance, clear latent images, wide viewing angles, slim structure, and large screen size, plasma display devices are considered to be the next generation display devices which will replace cathode ray tubes (CRTs).
A plasma display module includes a plasma display panel forming a front portion of the plasma display module to display images and a chassis base that supports the plasma display panel from a rear side of the plasma display panel. Circuit substrates that generate predetermined driving signals to be applied to the plasma display panel are mounted on a rear surface of the chassis base. The driving signals generated by the circuit substrates are transmitted to the plasma display panel through connection cables.
A heat dissipation sheet for transmitting heat generated by the operation of the plasma display panel to the chassis base may be interposed between the plasma display panel and the chassis base. A strip of double-sided tape that intermediates the coupling of the plasma display panel with the chassis base may be interposed between the plasma display panel and the chassis base in areas where the heat dissipation sheet is not interposed. The chassis base serves as a heat dissipation plate that dissipates heat transferred from the plasma display panel to the outside through by natural convection of air over an outer surface of the chassis base. At the same time the chassis base functions as a supporter that supports the plasma display panel disposed in front of the chassis base and the circuit substrates disposed on a rear surface of the chassis base. Therefore, the chassis base should have a mechanical strength greater than a predetermined level to safely protect the plasma display panel and the circuit substrates from an unexpected external impact. Meanwhile, the chassis base, formed of an electrically conductive material, has a wide area to provide a grounding region that maintains a constant ground voltage, and the circuit substrates mounted on the rear surface of the chassis base have a grounding structure that may be directly electrically connected to the chassis base through screw members coupled to the chassis base.
To manufacture the chassis base, a method of die-casting or pressing an aluminum material to a predetermined shape may be used. Accordingly, the cost of raw materials required may be high, thereby increasing manufacturing costs. Also, the chassis base formed of an aluminum material may be susceptible to bending or twisting due to its material characteristics. Therefore, when an external impact is applied to the plasma display module during transportation or moving, the plasma display panel and the circuit substrates cannot be protected by the chassis base, and therefore, may be damaged by the external impact. In particular, as the size of the plasma display panel increases, the size of the chassis base, which is proportional to the size of the plasma display panel, also increases, and therefore, becomes more susceptible to bending or twisting. Therefore, an additional reinforcing structure or reinforcing member for protecting the plasma display panel may be required.
Also, in that situation, the thickness of the chassis base, generally formed of aluminum, must be increased to ensure a predetermined strength. However, the increased thickness is undesirable for making a slim display module. Furthermore, the chassis base, formed of an aluminum material having a specific gravity of approximately 2.7, increases the total weight of the display module. Overall, the chassis base, formed of an aluminum material, may be a limiting factor in making a lightweight and slim plasma display module.
Recently, plastic materials are drawing attention as a new material for forming the chassis base since plastic materials having high strength are advantageous for making lightweight yet strong and slim display modules. However, when an insulating plastic material is used for manufacturing the chassis base, the circuit substrates cannot be grounded by conventional grounding method. Therefore, a new grounding structure for grounding the circuit substrates is required.